1. Field of the Invention
This invention relates generally to self-lubricating bearing and bushing liners, and more particularly to self-lubricating liners that provide good high temperature wear resistance without the brittleness of glass fiber.
2. Discussion of the Related Art
It is known in the art to utilize self-lubricating bearings or bushings to provide low wear rates in a variety of high load applications. Self-lubricating liners must be resistant to damage during use, as well as during the assembly process. Self-lubricating liners must be able to withstand the heat and pressure that may be associated with use. They must also be resistant to a variety of substances, including mild acids, alcohols, oils, and water.
It is also known in the art to produce bearings containing a fibrous surface liner containing polytetrafluoroethylene (PTFE) with polymeric fibers and a resin. The PTFE fibers adhere to the resin and provide a low coefficient of friction, thus minimizing wear. For example, U.S. Pat. No. 4,074,512, to Matt, discloses a resin-impregnated PTFE fabric for use in bearing applications. Fibrous material, such as carbon, glass fibers, aramid, or other common polymer fibers, may be added as well to self-lubricating liners to increase strength and inhibit wear. Such fibers are desirable to be interwoven with the PTFE to increase the compressive strength of the fibrous composite. Brittle fibers, particularly glass and carbon fibers, may tend to break either during the bearing manufacturing process or during use. Some common polymer fibers used as liner reinforcement are known to creep under load or thermally break down when subjected at elevated temperatures and compressive loads. Accordingly, an improved self-lubricating liner having increased durability and ability to withstand increased temperature and pressure is desirable.